Apparent digestibilities of energy, cell wall constituents, crude protein and amino acids of Chinese oil seed meals for growing pigs

Abstract

The apparent ileal and faecal digestibilities of energy, crude protein (CP), amino acid and cell wall constituents in feedstuffs of peanut meal (PNM), soyabean meal (SBM), rapeseed meal (RSM-1), ammoniated rapeseed meal (RSM-2), partly dehulled cotton seed meal (CSM) and rice bran cake (RBC) were determined for non-cannulated pigs ( n=6) or pigs ( n=6) fitted with ileo-caecal reentrant cannulae. The pigs were fed with a cornstarch-based diet formulated to contain about 14% protein. The results showed that the ileal digestibility of energy was not significantly different between SBM (76.2%) and PNM (74.4%), but that it was significantly lower for RBC ( P<0.05) than for SBM and PNM. However, the ileal digestibility of energy was significantly lower for RSM-2, RSM-1 and CSM than for RBC. The ileal digestibility of CP was significantly higher for PNM (87.3%) than for SBM, and was significantly higher for SBM than for RBC (73.4%) and CSM (73.0%). Although the ileal digestibility of CP was significantly higher for RSM-2 than for RSM-1, it was significantly lower for RSM-2 than for CSM and RBC. CSM had the lowest ileal digestibilities of lysine (43%), methionine (64%) and threonine (67%), which are the most important amino acids in amino nutrition. The ileal digestibility of lysine was highest for SBM ( P<0.05), but that of methionine was highest ( P<0.05) for RSM-2. PNM, SBM and RSM-2 had a similar ileal digestibility of threonine. PNM contained not only the highest amount of arginine (76.6 g kg −1 DM), but also had the highest ileal digestibility of arginine (92%). In general, the faecal analysis method overestimated the digestibility value of nutrients. The modifying action of the bacteria in the large intestine is irregular, therefore a precise determination of the apparent digestibilities of nutrients, especially the amino acids, cannot be obtained from the faecal analysis method. In contrast to previous findings, a high ileal digestibility of cell wall constituents was found for oil seed meal.